3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php $array = array('foo' => array('bar')); function foo() { return array('bar'); } var_dump(key(foo()));
based on vjbt9
Output for 4.3.0 - 5.0.4, 5.1.0 - 7.2.0
int(0)
Output for 5.0.5
Fatal error: Only variables can be passed by reference in /in/NGsPl on line 6
Process exited with code 255.